The disclosure relates to a drive device for moving hands by stepping motors, an electronic watch having the drive device, and a control method of the drive device.
For example, in an analog electronic watch disclosed in JP-A-2005-147727, a plurality of stepping motors drives hands such as an hour hand, a minute hand, and a second hand, respectively, whereby time is displayed. This hand movement is performed by applying drive pulse voltages to the stepping motors, thereby rotating the rotors of the stepping motors, and transmitting the torque of each rotor to a corresponding hand at a predetermined gear ratio by gear train mechanisms which are arrangements of gears, thereby rotating the hands.
In the analog electronic watch, for example, during correction on current time or switching of display modes or operation states according to or a user's operation on a stem or the like, the output frequencies of the drive pulse voltages for the stepping motors are controlled, whereby the hands are fast-forwarded.
In the technology disclosed in JP-A-2005-147727, when the plurality of stepping motors is controlled, after a previous control motor stops, the operation of the next control motor is controlled.
In the technology of Japanese Patent Application Laid-Open No. 2005-147727, the degree of freedom of control on hand movement start timings and hand movement speeds is low, and it is difficult to express hand movement more smoothly and more dynamically.